What is Solar Photovoltaics? (Solar PV)
The term ‘solar panel’ is often used interchangeably to describe the panels that generate electricity and those that generate hot water.
- Solar panels that produce electricity are known as solar photovoltaic (PV) modules. These panels generate electricity when exposed to light. Solar PV is the rooftop solar you see on homes and businesses.
- Solar panels that produce hot water are known as solar thermal collectors or solar hot water collectors.
The Solar electricity grant focuses on PV, where solar electric panels capture the light from the sun and convert it into the electricity that is used in your home to power your TV, kettle, toaster, phone charger, radio, oven, and so on.
Installation of domestic solar PV system
A domestic solar PV system consists of a number of solar panels mounted to your roof (or in your garden) and connected into the electrical loads within your building. The solar panels generate DC (direct current – like a battery) electricity, which is then converted in an inverter to AC (alternating current – like the electricity in your domestic socket). Solar PV systems are rated in kilowatts (kW). A 1kW solar PV system would require 3 or 4 solar panels on your roof.
Any excess electricity produced can be stored in a battery, or other storage solution like your hot water immersion tank. It can also be exported from your house into the electrical network on your street.
Generating electricity from solar PV
A solar electric system (PV) is typically made up of:
- Solar panels on the roof, which generate DC (direct current – like in a battery).
- An ‘Inverter’ which converts this to AC (alternating current – like the electricity in your house socket).
- Sometimes a battery on larger systems to save energy for later use.
Solar PV systems generate electricity during daylight hours only, predominately around the middle of the day. In Ireland, around 75% is produced from May to September. If this electricity is not used in the home it is exported to the grid.
It is desirable to maximise the amount of solar electricity you use in your home. You can do this by sizing the solar PV system to meet your demand.
We have structured our grant based on detailed analysis and research. It is in your interest to increase the amount of solar electricity you use in your home. However, there will be a trade-off between reducing the amount of excess energy exported to the grid and the additional costs for batteries or other energy storage systems.
On average, a solar PV system can save between €200-300 per year on your domestic electric bill.
What Solar PV system will suit my needs?
The size of the Solar PV system you purchase will depend on a number of factors,
- Amount of electricity you use in your home
- Time of day you are at home
- Orientation of your roof
Your selected installer should discuss all of the above factors with you. Your installer will also check your current and past electricity consumption to calculate the appropriate system size.
To understand the financial benefits, you should consider
- Payback period cost of installation
- Reduction in electricity required from utility provider
Research shows that 80% of the electricity produced by a 2kW (kilowatt) solar PV system (6-7 solar panels) would be used within the average Irish home.
When to invest
Before considering an investment in solar technologies, it is also important to assess the energy performance of the whole home. We recommend the following approach to improve the comfort of your home and reduce your carbon footprint:
- Ensure your home has a good energy performance rating (BER). This means insulating walls, attic and ensuring that you have good double or triple glazed windows.
- Upgrade your heating system by installing a heat pump.
- Consider Solar PV or Solar Thermal.
- The most suitable roof is south facing and generates the most electricity. However any roof in good condition with no shading could work well. Shadows on solar panels can greatly reduce their ability to generate electricity, especially those caused by objects less than 10 metres from the panels.
- Solar panels are expected to last over 20 years. Your Installer should check that your roof is in good condition for a PV system.
- Installing solar panels on your roof will typically mean that additional timber roof support needs to be added to you roof. The solar panel racking system is attached to these new timber supports.